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The Oak Stands Tall

The eastern United States' mightiest tree, the oak, is in decline, possibly due to over-harvesting or climate change. Whatever the cause, scientists are trying to find ways to reverse this decline. Watch U.S. Forest Service researchers use fire to give young oaks room to grow in the North Carolina mountains.

ASHEVILLE — The sounds echo through an otherwise silent forest.

“Are you ready?” one voice calls out. Then one by one, a technician with the U.S. Forest Service calls out the type and size of a plant. One technician notes all of them on the clipboard. All of the plants inside a radius of roughly four feet are identified and noted.

You’ve got to know your forest to take inventory of it. And these technicians know what lives in this oak dominated hardwood ecosystem, which is a part of the Bent Creek Experimental Forest in Asheville.

“We have permanent inventory plots scattered throughout the burn unit, and our technicians come in before the burn and after the burn and take inventory of the regeneration and see how it responds to the treatment,” explains Tara Keyser, a research forester with the U.S. Forest Service.

The forest service is experimenting with the reintroduction of a totally natural technique to help manage and preserve the oaks in the southern Appalachian Mountains, where oaks were a once dominant species. Mother nature used this technique extensively before and during the early European settlement of the area.

It's called fire.

“We are looking at how prescribed fire helps hardwoods in the regeneration layer as well as the overstory layer,” Keyser explains.

The U.S. Forest Service hopes this technique will help renew the declining oak species in the area. Fire suppression is one possible reason for the decline in the first place, as thick forest floor plantlife makes it difficult for oak trees to grow. Other possible reasons include pests, climate change that favors other types of trees, or even the increased consumption of acorns and seedlings by growing mammal populations.

While the forest has important small tree and bush habitats along the forest floor as well, the U.S. Forest Service is focusing on fostering oak growth to restore its lush population. The fire technique may be helping to do just that.

The forest area was subject to a controlled burn in 2013 and again in 2014. Technicians made an inventory of what was growing here before the fire and then at regular intervals after the burn. They will continue surveying the area for the next three years.

Walking through the area roughly one year after the latest fire, it was amazing to see just how much was growing. There were small shrubs and dozens of small oak trees that were about three feet tall.

“It’s too early to tell if this is a successful outcome of the burn, but this is a red oak and you can see its top was killed by fire,” Keyser explains, as she moves closer to the sapling to inspect it. “Small trees are susceptible to mortality because of fire, but all the hardwood tree species in this ecosystem sprout back and this has sprouted back after being top killed.”

In general, oak trees are able to tolerate fire more because they have a much thicker bark. Maple trees have a thin bark, so they can't withstand the heat as well.

As you hike through the Bent Creek Experimental Forest, you gain a better understanding of the U.S. Forest Service study. The forest area that was burned is more open; the forest floor is missing a lot of the shrubs and thickets. You can easily spot the burn marks on the bark of the oak trees. But being a more open forest means sunlight can reach the ground, which encourages more trees to grow. It’s also a more open area for wildlife.

Compare that with the forest area that’s been left to grow untouched. The understory between the tall trees is filled with smaller trees and bushes. It’s very dense, making it difficult for the prominent oak species to grow.

“In these oak dominated systems, we are often managing for the oak component," says Keyser. “We’re trying to sustain the oak component across the landscape and over time, we have lot of tools to do that, including fire, timber harvesting, and herbicide. So we have a lot of tools to accomplish that management objective.”

Using the natural fire technique and more, the U.S. Forest Service hopes to rescue the oak species, and restore the area to its oak dominated state.